snd_hda_intel initialization failure with Xen PCI passthrough

[Jason Andryuk]

On Wed, Mar 23, 2022 at 5:41 AM Takashi Iwai <tiwai at suse.de> wrote:
>
> On Tue, 22 Mar 2022 19:57:27 +0100,
> Jason Andryuk wrote:
> >
> > Hi,
> >
> > I'm running Xen hypervisor and using PCI passthrough to assign an
> > Intel HDA audio device (00:1f.3 Audio device: Intel Corporation Cannon
> > Point-LP High Definition Audio Controller (rev 30)) to a Xen HVM
> > virtual machine.  I do this for both Linux 5.4.185 and a different
> > Windows 10 VM (only one at a time).  The Windows VM seems to work
> > every time.  The Linux VM has issues after the first VM boot.  This is
> > one boot of the physical hardware and multiple boots of the virtual
> > machines.
> >
> > For Linux, on first boot, the sound card is detected and works
> > properly.  After that, things usually don't work.  I just ran a reboot
> > loop and it was:
> > 1st boot - audio detected and working
> > 2 & 3 - no audio
> > 4th - audio detected and working
> > 5 - 20 - no audio
> >
> > For boots 2, 3, 5-7, dmesg shows:
> > [    0.760401] hdaudio hdaudioC0D0: no AFG or MFG node found
> > [    0.760415] snd_hda_intel 0000:00:06.0: no codecs initialized
> >
> > For boots 8+, the errors changed to:
> > [    0.783397] hdaudio hdaudioC0D0: cannot read sub nodes for FG 0x10
> > [    0.783413] snd_hda_intel 0000:00:06.0: no codecs initialized
> >
> > At this point, I booted a Windows 10 VM and audio works
> >
> > Trying to boot Linux again gives a new error message
> > [    0.789041] snd_hda_intel 0000:00:06.0: Unknown capability 0
> > [    1.811205] snd_hda_intel 0000:00:06.0: No response from codec,
> > resetting bus: last cmd=0x0eef0004
> > [    1.811246] hdaudio hdaudioC0D0: cannot read sub nodes for FG 0x10ee
> > [    1.811263] snd_hda_intel 0000:00:06.0: no codecs initialized
> >
> > Reboot VM and it's back to:
> > [    0.775917] hdaudio hdaudioC0D0: no AFG or MFG node found
> > [    0.775932] snd_hda_intel 0000:00:06.0: no codecs initialized
> >
> > Reboot VM and again:
> > [    0.789069] hdaudio hdaudioC0D0: cannot read sub nodes for FG 0x10
> > [    0.789084] snd_hda_intel 0000:00:06.0: no codecs initialized
> >
> > Reboot physical laptop:
> > 1. boot Windows 10 - audio works
> > 2. boot Linux - audio works
> > 3. reboot Linux - no audio
> > [    0.773111] hdaudio hdaudioC0D0: no AFG or MFG node found
> > [    0.773151] snd_hda_intel 0000:00:06.0: no codecs initialized
> >
> > This seems to me like Windows does a better job resetting the card to
> > get the audio hardware working.  Any suggestions on what to
> > investigate?

Thanks for taking a look, Takashi.

> First off, 5.4.x is way too old to debug, please confirm the issue
> with the latest kernel.
>
> And, one test I'd try is to unload snd-hda-intel module before
> rebooting.  Does the problem persist?

For my 5.4.186 VM, the module is built-in.  I tried `echo 0000:00:03.0
> /sys/bus/pci/driver/snd_hda_intel/unbind` before rebooting, but that
did not work.

I switched to Fedora 35 in the VM with kernel 5.16.16.  That worked
the first time and failed the second.

First working:
[    3.094907] snd_hda_intel 0000:00:06.0: DSP detected with PCI
class/subclass/prog-if info 0x040380
[    3.094912] snd_hda_intel 0000:00:06.0: NHLT table not found
[    3.197480] snd_hda_codec_realtek hdaudioC0D0: autoconfig for
ALC3204: line_outs=1 (0x14/0x0/0x0/0x0/0x0) type:speaker
[    3.197484] snd_hda_codec_realtek hdaudioC0D0:    speaker_outs=0
(0x0/0x0/0x0/0x0/0x0)
[    3.197485] snd_hda_codec_realtek hdaudioC0D0:    hp_outs=1
(0x21/0x0/0x0/0x0/0x0)
[    3.197486] snd_hda_codec_realtek hdaudioC0D0:    mono: mono_out=0x0
[    3.197487] snd_hda_codec_realtek hdaudioC0D0:    inputs:
[    3.197488] snd_hda_codec_realtek hdaudioC0D0:      Headset Mic=0x19
[    3.197489] snd_hda_codec_realtek hdaudioC0D0:      Headphone Mic=0x1a
[    3.197489] snd_hda_codec_realtek hdaudioC0D0:      Internal Mic=0x12
[   66.801958] snd_hda_intel 0000:00:06.0: azx_get_response timeout,
switching to polling mode: last cmd=0x00170500

Second boot audio still failed after doing `echo 0000:00:06.0 >
/sys/bus/pci/driver/snd_hda_intel/unbind` and rmmod-ing lots of snd_*
modules.  I rmmod-ed the snd_*intel ones, but other snd* modules
including snd_hrtimer were in use and could not be removed.
[    2.850918] snd_hda_intel 0000:00:06.0: DSP detected with PCI
class/subclass/prog-if info 0x040380
[    2.850923] snd_hda_intel 0000:00:06.0: NHLT table not found
[    2.873157] hdaudio hdaudioC0D0: no AFG or MFG node found
[    2.873161] snd_hda_intel 0000:00:06.0: no codecs initialized

A different second boot where audio failed:
[    2.892183] snd_hda_intel 0000:00:06.0: DSP detected with PCI
class/subclass/prog-if info 0x040380
[    2.892189] snd_hda_intel 0000:00:06.0: NHLT table not found
[    2.961762] hdaudio hdaudioC0D0: cannot read sub nodes for FG 0x0e
[    2.961768] snd_hda_intel 0000:00:06.0: no codecs initialized

Thanks,
Jason